The present invention relates to a microcomputer, an electronic instrument, and a protection method for a flash memory provided in a microcomputer.
A protection control method using a flash writer is known for a microcomputer including a flash memory. On the other hand, a microcomputer including a flash memory generally does not have a protection function (see JP-A-59-5496 and JP-A-2002-269065).
Since related-art technology requires a protection cancellation key or a complicated protection circuit, or suffers from security holes, it is difficult to provide the entire flash memory with read protection.